(a) Field of the Invention
The present invention relates to the composition of molecular assemblies in liquid solution that enables temperature-controlled pH-dependant formation of biopolymeric gels, such as polysaccharide-based, and methods of preparation thereof.
(b) Description of Prior Art
Biopolymers and macromolecules are attractive materials for the preparation and design of self-gelling and/or auto-assembling systems. Numerous attempts tend to develop such systems on the basis of polysaccharides and polypeptides.
In situ formed gels were also proposed with ionic polysaccharides. A composition can be used as a medical device for drug delivery, the application of a diagnostic agent, or the prevention of post-operative adhesions, and is composed of an aqueous liquid vehicle which is capable of being gelled in situ. It includes at least one ionic polysaccharide, at least one film forming polymer, and a medicament or pharmaceutical agent, water, and optionally, a counter-ion capable of gelating the ionic polysaccharide. However, the gelation is reached by interaction between the ionic polysaccharide and the film-forming polymer, or by counter-ion induced cross-linking of the ionic polysaccharide. Other in situ forming gels are based upon polyoxyalkylene composition or polyoxyalkylene/polysaccharide mixture or alginate/cation mixture in situ.
It would be highly desirable to be provided with a biopolymeric gel that is formed while excluding any organic solvent, any organic monomers, any ionic or covalent cross-linking that may be potentially toxic or induce a reduced biological compatibility.
It would be highly desirable to be provided with a biopolymeric gel that is formed by stimulus-induced free interactions between biologically acceptable and well-recognized molecules.
It would be highly desirable to be provided with, a temperature-controlled pH-dependant formed biopolymeric gels that could be used to encapsulate cells and cellular material while retaining their biological activity.
It would be highly desirable to be provided with such gels, which would retain its solid or gel state at the physiological temperature or 37° C.